Automatic call-distributing system.



J. G. ROBERTS;

AUTOMATIC CALL DISTRIBUTING SYSTEM.

I26 mu 7 APPLICATION FILED .UNEZB. 1913 Patented Dec. 14, 1915.

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J. G. ROBERTS.

AUTOMATIC'CALL msnusunue SYSTEM.

APPLICATION FILED JUNE 26. I9I3.

Patented Dec. 14, 1915.

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[ UNITED STATESPATENT OFFICE.

JOHN G. ROBERTS, 0F DOBIBS FERRY, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

AUTOMATIC CALL-DISTRIBUTING SYSTEM.

5 and State of New York, have invented a certain new and useful Improvement in Automatic Call-Distributing Systems, of which the following is a Full, clear, concise, and exact description.

This invention relates to telephone exchanges, and its object is to connect the lines of calling subscribers with call receiving equipment at the central otiice instantly and with precision and economy of a ')paratus.

The subscribers lines of any exchange may be divided into groups of, say,'fii't v lines, all of the subscribers of each group having instant access when calling to a common instruction circuit and preferably also one section of an automatic line switch. This switch has access, preferably by a single quick movement, to an idle call receiving apparatus which may be an operatofs telephone. The operator may thereupon receive instructions from the calling subscriber, and on establishing the desired connection the instruction circuit and automatic switch revert to common use.

' The invention will be more fully understood by reference to the accompanying drawings, wherein--' Figure 1 is a diagram of a system of circuits embodying the invention; Fig. 2 is a view showing a type of automatic switch suitable for connecting the common instruction circuits for the several groups of subscribers to idle operators equipment; Fig. 3-15 a fragmentary perspective view of the frame of the'automatic switch; and Fig. 4 is a detail of a locking and releasing device of the switch.

In the drawings, a plurality of batteries are shown to represent sources of current, but it will be understood that preferal ly, as in practice, some or all of such batteries" may be replaced by one which. will serve as well as a common source fortheseveral circuits.

Referring to the diagramin Fig. 1, a callingsubscriber, say at substation 101, in a tion circuit CHIl'l}')l'lSl11 a pair of wires 7. 8

I leading to an automatic switch 10-3. this being the switch shown more in detail in Fig.

Specification of Letters Patent.

manner to be presently explained in detail,

Patented Dec. 14, 1915.

Application filed June 26, 1913. Serial No. 775,927.

This switch thereupon instantly extends the circuit through a pair of conductors such as 9, 10, leading to an idle operators telephone equipment 108. The idle operators equipment is nit-selected by an automatically adjusted branch circuit system, so that the operator is ready to receive instructions at once from the calling subscriber who niakes known the number of his own telephone station as well as that of the subscriber wanted. 'lhereupon the operator mav pick up an idle answering plug 109 of a link circuit, insert it in a multiple jack 110 connected with the calling line, and insert the companion plug 146 in the multiple jack of the line wanted. The act of connecting, the link circuit with the calling line operates the cutoff relay 111, disconnecting the instruction circuit before mentioned and the apparatus associated therewith from the calling line. The instruction circuit then reverts to the use of any other subscriber of the same group that may be calling. If the operator desires to make a talking circuit for herself with the calling or called subscriber after the plug connection is put up, she may do so by means of her listening key 112 associated with the cord in use.

Either the receipt of a call over the instruction circuit or the actuation of any listening key of an operators position renders that position busy so that other calls will not be received by her while attending to the one in hand. The operators equipment may be maintained in a busy condition in a variety of ways. In the system shown it is determined by the operation of a relay 113 which is common to the link circuits of her position, two other similar relays 114 and 115 being located and serving a similar function at other operators positions. Relay 114 may be assumedto be at the first operators position, l13at th nth position, and 115 at the next position beyond n; As shown in the diagram, a circuit is closed through the back contact of relay 113, (except for the open switch contact 20 of a magnet 18) associated with the automatic switch 105. This circuit maybe traced as follows:from grounded battery 116 through contact 20, magnet 18, conductor-117, back contact of relay 113, conductor 118, frcnt Contact of relay 114 to ground. It is i...sumed that the first operator with whose position relay 114 is asso- 3, 4, 5 and 6, 3 and 4 being terminals of the incoming line 7, 8, and 5 and 6 of theoutgoing line 9 and 10. These spring terminals.

preferred for the connection to the I ciated, and all the other operators between her position and the position at which relay 113 is located, are busy. At the moment that this circuit just traced had been closed, magnet 18 had been energized-and its armature 28 attracted. The armature is then held by means of a common itself'is the subject-matter'of another-applb cation of this applicant, Serial No. 766,772, filed May 10, 1913. It is, as will appear from the description, a switch mechanism capable .of rapidly distributing successive incoming calls from a plurality of incoming circuits, such as the instruction circuit 7, 8, to difierent outgoing circuits, such as the operators circuit 9, 10.

Referring1to Fig. 2, 1, 1, 1 are incoming line shafts extending horizontally, and

2, 2, 2 intersecting outgoing line shafts ex-' tending vertically. At oradjacent each intersecting pointis a set of contact springs are mounted rigidly in a frame 11 at one side of-the intersecting shafts, the springs '3 and .4 being connected in multiple with like springs of other contact sets in the same horizontal rowby means of plates 12,

13, of which these springs are an integral part or with which they are in contact. The outgoing line springs 5, '6 are likewise connected in multiple with like springs of conl tact sets in the same vertical row, the-connections in this case being made by 1 wires .14, 15 soldered to the ends of the springs at the rear of the frame. The body of the frame may .be of insulating material as shown, and the contact springs held therein rigidly but insulated from one another ex cept for .the multiple connections before mentioned. v

Surrounding the body'of the frame are supporting strips 16 (indicated in part by dotted lines) provided with holes to form bearings for the shafts and formed in a manner to be presently described for supportingthe electromagnets and their operating parts. Electromagnets 17 (one only being shownin Fig.2 in full) are placed in vertical alinement along the side strip 16,

" while electromagnets 18 (also one only shown) are similarly alinement along the bottom strip 16. Each in horizontal magnet may have an individual set of conarmature 28 for the magnet 18.

the wedge an 'ment 'with the contact springs 20 which are tact springs such as the set 19 for the ma et 17 and set 20 for the magnet 18.

ach of the shafts 1 extends through to the outside of the side strip 16 and carries an armature21 for the magnet 17. An ex: tension 22 of this armature carries a roller '23 which is" in position to engage the set of contact'springs 19 when the armature is attracted. Fastened at one end to this extension 22 and at the other end to an extension 24 of the strip 16 through an opening 25 therein is a retractile spring 26 which normally holds the armature 21 away from the ma et core and against a stop formed by the inturned art 27 of the extension 24. The lower 'en Pointing outwardly and downwardly from the armaof each shaft 2 carries an ture 28 is a projection 29 which, when the r armature is attracted, engages the upwardly inclined-edge 30 of a latchi device, shown as a rocking plate 31 (see Fig. 4), and is in turnengaged by the latter to hold the armature and 1ts shaft 2 in displaced position.

Extending upwardly from the armature 28 is a pin 32 to'which one end of a retractile spring 33 is attached,'the other end thereof bein attached to a usshaped strip 34 secure .at each end to the side strips 16. A pivotscrew 35, one at dach end of the strip 34, engages the ends of the rocking plate 31 and a retractile spring 36, for the latter is secured. at one end to a in 37 in the, side strip 16 and fastened at its other end to an extension 38 which projects through an opening in an arm of the U-sha d strip 34.

The endof the pin '32 plays I arms of an L-shaped wedge 39 pivoted and secured by a screw 40 to an arm- 41 of the spool-head .of the magnet 18. This wedge carries an insulating button 42 positioned beneath an inclined end of oneof the springs of the contact set 20. In the position shown, the armature 28 is retracted against a back stop pin 55 in the lower strip 16, the pin 32 is in enga ment with the-short arm of (fihe button 42 is out of engagenow in contact with each other. When, how ever,'the armature is attracted, as by the closure at contact 43 of a circuit 44 including the magnet 18 'and contact 20, the pin 32- tween two engages near the end of its stroke the long 1 arm of the wedge, movin against-the inclined end 0 the spring and opening the circuit 44. A projection 29 of the armature 28 being caught by the latching device, the shaft 2 remains displaced and although there is a. slight retractory move- 'ment of the armature when the circuit is opened, the wed 39 retains its advanced position due to riction between the button 42 and the spring, "thus reventing the circuit 44 from being cl again at the contact set 20. The release of the latched arthe button 42 mature and shaft 2 is subsequently effected by displacement of the rocking plate 31 whenever any other magnet 18 is energized.

When this occurs the projection 29 of the last operated magnet engages the inclined surface 30, tilting the plate 31 and releasing the first operated armature and shaft, the last operated armature and shaft becoming locked in the same manner as the other one had been. The return movement of the armature 28 carries the pin against the short arm of the wedge 39, withdrawing the latter from the contact set 20 and allowing the circuit 44 to be closed again at thatpoint ready for a subsequent operation oy closure of contact 43.

For operating each contact set 3, 4, 5 and 6 at the intersections of the shafts, there are provided two arms, one a flexible arm in the form of a spring wire 45 carried by shaft 2, and a rigid arm 46 attached to shaft 1. The

arm 45 is protected from displacement by a rigid arm 47, the latter being directly attached to the shaft 2 and the former attached to the latter at a point near the shaft. The arm 47 is turned down at its free end over a right-angle extension 48 of the arm 45, and at the free end of this extension the arm or wire is formed in an upturned half loop 49, which is adapted to engage the recess 50 in the arm 46. The contact set 3, 4, 0 carries a headed insulating plug 51 inserted in a hole near the end of spring the head resting on that spring and the lower end of the plug resting on spring 4.

The magnets 17 and 18 are controlled by the circuits shown in Fig. 1.

'In the operation of this switch mechanism some one of the outgoing lines, such as 9. 10. will be prepared for subsequent connection to any incoming line. The magnet 18 having attracted its armature and latched the armature and its shaft 2 in angular displacement in. the manner before described, each of the flexible arms 45 carried by this shaft will be swung to the left, bringing its half looped end 49 directly over the head 52 of a contact set and beneath the rigid arm 46 of a shaft 1. The subsequent closure of the circuit of magnet 17, will rock the corresponding shaft 1, causing the rigid arm 46 to descend upon the end 49 of the flexible arm 45, pushing the latter against the head of the contact set located at the intersection of the two shafts 1 and 2 which have been displaced. In this manner the springs 3, 4 are brought into contact with springs 5, 6, respectively, and

the connection is established between the incoming line 7, 8 and the outgoing line 9, 10. As soon as the connection just described is made, thepreviously displaced outgoing line shaft 2 is released and another shaft 2 dis-, placed to prepare another outgoing line in condition for subsequent connection to any incoming line. The end 49 of the flexible arm 45 fits snugly between the arm 46 and the head 52 of the contact set, and is held there by the recessed arm 46 when the shaft 2 is restored. Inthis manner the contact set is maintained operated merely by the con- 70 tinued displacement of the mcomin line shaft 1. It will be noted also that wh le the incoming line shaft is displaced the subsequent displacement of any outgoing line shaft 2 will not result in the operation of the. 1 contact set located at the intersection of those shafts, for the reason that the end 49 of the flexible arms 45 will not enter between the arm 46 and the head 52, but will strike the edge of the arm 46 and be held in so that position until the line shaft 1 is restored.

The functions of the various pieces of apparatus shown in Fig. 1 and not heretofore referred to will be understood from the following detail statement of the operation of 35 the system. Assuming a call to originate at subscribers station 101, the subscriber lifts his receiver closing the line circuit from grounded battery 107 through the back contact 120. winding of relay 102 and a non- 9 0 inductive shunt 106 thereof, back contact 121 of cutoff relay 111, line wire 122. hook switch. receiver and transmitter at station 101, line wire 123, back contact 124. of cutoff relay 111, and back contact 125 of relay 102 to ground. This causes the energization of relay 102 which disconnects battery and ground from the circuit just described and extends the line circuit to the conductors 103. 104 of the common instruction circuit for 160 that group of stations which includes station 101. 'Iheeatended line circuit may nou be traced from grounded battery 126 through back contact 127 of switch magnet 17, the winding of said magnet 17 and a non-inductive shunt 128 thereof. conductor 104, front contact 129 of relay 102, and thence by way of the circuit before traced (excluding the -battery 107 and ground) to the front contact 130 of relay 102. conductor 103 and back no contact 131 of switch magnet 17. Theautomatic switch 105 now operates. instantly disconnecting battery and ground from the cir-. cuit just traced and extending the circuit to the conductors 9. 10 leading to the idle operators equipment 103. The line circuit as thus extended may be traced as follows: from grounded battery 132, relay 113, back contact 133 of the relay 134 (common to the operators position) conductor 10, springs 6, 4 closed by the automatic switch 105, conductor 8,"and thence by way of the just described circuit (exceptfor the battery 126 and ground) to conductor 7. springs 3, 5 also closed by the automatic switch 105, conductor 9 and impedance coil 135 to ground. It will be noted that the operators telephone 136 is connected in bridge of this circuit through a condenser, induction coil winding and back contacts 137 and 138 of relay 134. 13c- The subscriber then announces to the operator the number of his own telephone station and that of the subscriber wanted. The

operator proceeds to put up a-telephone circuit for the subscribersby first inserting an answering plug 109 of oneof her'idle cords or link circuits into the multiple jack 110, in her switchboardsection, corresponding to thenumber of his station given by the call- Y as ing to the number of the called station. The I ing subscriber. She then completes the connection desired by inserting the connectin 146 into a-multiple jack, correspon operator" may then actuate a ringing key 139 in the usual way to call the wanted subscriber to-his-telephone. It will be noted -that when the answering plug 109 was in- .serted in the multiple jack 110 a circuit was '1' closed for the cutoff relay 111 as follows:

from 'batte '140, through resistance 141,

supervisory amp 142, the sleeves-of the plu 109 and-jack 110, conductor 143 andcuto relay 111 to. ground; and a circuit was also closed for the subscribers line as follows:

from battery 140, through one leg 1440f a repeating coil, supervisory relay 145, ring contacts of the plug 109 and spring-j ack 110, branchconductor-191 of the line, line wire 122, substation .a paratus 101, line wire 123, branch 147 of t e line, tip contacts of the spring-jack 110 and plug 109, and another leg 148 of the repeating coil, to ground. The -cutofirelay opens at its back contacts 121 and 124 the line connection to the instruction circuit. This results in the deenergization of magnet 17. and relay 102. Both of these devices-are thus restored to .normal condition and the automatic switch 105 and in:

' struction circuit 103, 104 revert to common In case an operator desires to supervise a completed connection she may do so in the usual way by actuating her listening key 112. This key has, in addition'to the usual contacts 149 and 150 for thepperators telephone, a local'circuit contact 151. The func 7 tion of the latter is to close'circuit for relay 134 which when the key is depressed disconnects the operators telephone equipment from the conductors 9, 10 of the instruction circuit and connects themto a pair of conductors 1 52, 153 leading to the contacts 149 and 150, respectively, of the listening keys of all the cords at her position. The contact 151 is likewise multiply connected to like contacts on-the listening keys of other cords at this operators position. Therefore, when an of her listening keys is actuated, the cirmat is closed for relay 134 as follows: from ded, battery 154, through conductor 155, contact 151, conductor 156, and relay 134 to ground. The energization of relay 134 disconnects, as heretofore stated, the operators telephone from the instruction circuit and connects it in bridge of the cord cirfrom tions have access an cuit corresponding to the actuated'listening key. This bridgemay be traced as follows:

from conductor 157 of the cord circuit through contact 149 of the listening key, con- 'ductor' 152, frontcontact 158 of relay 134,

the operators telephonereceiver 136, the

condenser and induction coil winding, front contact 159 of relay 134, conductor 153 and contact 150 of the actuated listening key to conductor 160 of'the cord circuit. Relay 134 whenenergized performs the further function of maintaining the operators position busy. This is accomplished by the closure of a circuit for the relay 113 as follows:

grounded battery 132 through relay .113, front contact 161 ofrelay 134 and resistance 162-to ground.

It may be mentioned that whenever relay 113 is energized, as by a call being received over the instruction circuit another branch such as the branch 184 of the preselector circuit 118 is closed to another magnet, such as magnet 119, thus preselecting another idle operator to receive the next succeeding call. The other subscribers stations of the same group as thatincluding station 101 have access to the common instruction circuit in the same manner and by like apparatus and connections as shown for station 101. Such another connection is indicated by the branches 163, 164. Similarly, other connections from the conductors 7, 8 than the one to the operators equipment 108 by way of conductors .9, 10 may be made to other operators equipment. Such another connection is indicated by the branches 165, 166, which may be connected to conductors group including station 101. In thesame exchange other grou s of subscribers stamay be connected to their common instruction circuits, one such circuit being indicated by the pair of conductors 17 3, 174; and this pair has branches such as the pairs 175, 176 and 177, 178 lead- 3, 4, 5 and 6, and which ing through spring contacts of another section of the automatic switch 105.- The conductors 180, 181, 182 and 183 of this switch are connected in multiple with similar conductors at other sections byway of-the con-- ductors 9, 10, 167 and 168 respectively.

It will appear from the foregoing desri tion that in an exchange, say of 5000 su scribers, divided into 100 groups and having access to say. twenty operators positions, each grbup of fifty subscribers has a common instruction circuit leading to one section of an automatic switch adapted to they originate.

connect thatcircuit instantly with a prese-' of the various sections of the switch. In

the example assumed, there would be one hundred horizontal and twenty vertical sections'of the automatic switch 105. And it will be noted that the automatic switch, when it has established an instruction circuit to one operator, is immediately readjusted sons to extend the next succeeding call to another idle operator. The calls are thus distributed to idle operators as fast as Whenever two subscribers of a single group of-fifty subscribers happen to call at the same time, the operator receiving both calls may secure the numbers of both calling subscribers and put up separate connections for them in the jacks. It-

will be noted, however, that the probability of a plurality of calls arriving at the same time to the same position is slight because the groups are small and the instruction circuit is only used for a very'brief time for each call.

I claim: I

1. In a telephone system, the combination I with groups of telephone lines and link circuits therefor, of an instruction circuit common for the use of the lines of each group, a relay for each line adapted to connect said line when calling with the associated instruction circuit, a plurality of call receivers, means for connecting any of said instruction circuits when a line is connected thereto to an idle call receiver, and restoring means for said relay and said connecting means operative upon the connection of a link circuit with the calling line;

2. In a telephone system, the combination with groups of subscribers lines and link circuits therefor, of an instruction circuit for each group of lines, means for connecting a calling line of any group with the associated instruction circuit, call receiving apparatus, automatic switch mechanism .to distribute subscribers calls from a plurality of said instruction circuits to idle receiving apparatus, and restoring means for said instruction circuit and said mechanism operative upon the connection of a link circuit with the calling line. i

3. In a telephone system, the combination with groups of telephone lines and a plurality of call receivers therefor, of call distributing apparatus vcomprising instruction circuits, one for each group of lines, and switching apparatus adapted to connect a calling line with the instruction circuit as-,

sociated with its group and the said instruction circuit with an idle call receiver.

In witness whereof, I hereunto subscribe my name this 23rd day of June A. D., 1913.

JOHN G. ROBERTS.

\Vitnesses:

MURRAY V. boNA'rY, W. H. BROWN. 

